New Zealand: If you're eating lunch at your desk, you could double the chances of developing a fatal blood clot, experts have warned. A survey found three out of four young office workers were failing to take a lunch break.

But after 90 minutes of immobility the flow of blood to the vein behind the knee drops by 50 per cent. ComRes conducted a survey of 1,000 young professionals aged 21 to 30 and video gamers aged 16 to 21 and found that three quarters of the office workers (73 per cent) admitted to taking lunch at their desk. And nine out of ten of the gamers played for longer than 90 minutes without a break.

A separate survey of 400 workers by Dr Richard Beasley, director of the Medical Research Institute of New Zealand, revealed a 2.2-fold increased risk of blood clots among those who usually ate lunch seated at their desk.

"People know that a sedentary lifestyle increases the risk of obesity, diabetes and cardiovascular disease in later life. However, very few are aware of the fact prolonged immobility in the workplace also poses an immediate threat," a daily quoted him as saying. "People must be educated regarding the risks associated with sitting down for long periods," he added.

It is estimated there are over 60,000 cases of potentially fatal blood clots in the UK each year caused by deep vein thrombosis.